Other Planning LL with PGNiG

– Other

PSA: Q

The question of how PGNiG relates to the fact that the estimated annual
probability of loss of MSF (Main Safety Function) load-bearing structure due to collision
with visiting vessels exceeds PGNiG’s own acceptance criterion for collision loads has
not been satisfactorily answered. PGNiG states in its response that there will be a focus
on reducing collision risk for visiting vessels in accordance with ALARP by introducing
mitigating measures. Some such measures are stated in the answer. Correct use of
ALARP means that you must first ensure that the risk is within the acceptance criteria
you have, and that you must then reduce the risk further as far as possible (ALARP), cf.
the Framework Regulations §11 on risk reduction.
We request that PGNiG explain how to achieve acceptable collision risk, document this
and explain which further risk reduction measures (ALARP) are planned.

PSA: A

PUN will achieve acceptable risk by reducing the average vessel
displacement to 7500 tons. Frequency for loss of main safety function will
then be 9.8E-05, which is equal to a return period of 10 195 years.
Also, as part of the collision study, a sensitivity assessment was prepared.
Increasing probability for successful evacuation from 50-75% after damage
resulting in flooding of more than two compartments will also reduce the risk
to 6.3E-05.
PUN have used the JIP method for calculation of Collision risk for visiting
vessels and some of the assumptions used is 156 visits pr year (3 a week) and
a vessel displacement of 8070 tons. The risk calculation is based on statistics
from events in the past. The velocity of impact used in the calculation is based
on the average speed used in previous incidents, but most vessels have
procedures for reducing the speed below 1,54 m/s when entering the safety
zone, which is according to GOMO Guidelines. These procedures are verified
by PUN Marine Advisor and will be adhered to.
PUN refers to the AfC for risk reducing measures related to the visiting vessel
collision risk. Hence, no additional compensating measures than already
submitted.